Alasdair Wilkins

There's an old fringe theory that the Sun isn't our system's only star, that a red dwarf star named Nemesis is hiding out in the Oort Cloud. We've never found any evidence for it or any other secret companion star, and if this simulation is any indication, that's very good news for the gas giants.

The short video above shows one possible result of a series of computer simulations undertaken by researchers at the University of Toronto. The video imagines what would happen if Earth were located in what's known as a wide binary system, in which the system's planets orbit one main star while another star maintains a distant, increasingly eccentric orbit much further out.

Admittedly, the video isn't an exact match for Nemesis — that's supposedly located 1.5 light-years away, while this video imagines a star that starts its orbit at a tenth that distance — but it does reveal just how remarkably unstable such wide binary systems can be. The panel on the left shows the Sun and its distant part, while the right panel zooms in to show the effects on the gas giants Jupiter, Saturn, Uranus, and Neptune.

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In this particular simulation, first Neptune and then Uranus are ejected thanks to the incredible gravitational disruptions caused by the second star. Researcher Nathan Kaib of the University of Toronto explains just why this happens in a statement:

"The stellar orbits of wide binaries are very sensitive to disturbances from other passing stars as well as the tidal field of the Milky Way. This causes their stellar orbits to constantly change their eccentricity – their degree of circularity. If a wide binary lasts long enough, it will eventually find itself with a very high orbital eccentricity at some point in its life. This process takes hundreds of millions of years if not billions of years to occur in these binaries. Consequently, planets in these systems initially form and evolve as if they orbited an isolated star. It is only much later that they begin to feel the effects of their companion star, which often times leads to disruption of the planetary system."

In almost half of all their simulations, the researchers found that the distant companion star ejected at least one of the gas giants, suggesting this would be a very common outcome in the galaxy's countless wide binary star systems. Indeed, according to fellow researcher Martin Duncan on Queen's University, we may already be seeing the aftereffects of such disruptions in the systems of recently discovered exoplanets:

"We also found that there is substantial evidence that this process occurs regularly in known extrasolar planetary systems. Planets are believed to form on circular orbits, and they are only thought to attain highly eccentric orbits through powerful and/or violent perturbations. When we looked at the orbital eccentricities of planets that are known to reside in wide binaries, we found that they are statistically more eccentric than planets around isolated stars like our Sun. Recently, planets orbiting at wide distances around their host stars have been directly imaged. Our work predicts that such planets are common but have so far gone largely undetected."